1 2 3 4 5 6 7 Network Working Group R. Weltman 8 Request for Comments: 3829 America Online 9 Category: Informational M. Smith 10 Pearl Crescent, LLC 11 M. Wahl 12 July 2004 13 14 Lightweight Directory Access Protocol (LDAP) 15 Authorization Identity Request and Response Controls 16 17 Status of this Memo 18 19 This memo provides information for the Internet community. It does 20 not specify an Internet standard of any kind. Distribution of this 21 memo is unlimited. 22 23 Copyright Notice 24 25 Copyright (C) The Internet Society (2004). 26 27 Abstract 28 29 This document extends the Lightweight Directory Access Protocol 30 (LDAP) bind operation with a mechanism for requesting and returning 31 the authorization identity it establishes. Specifically, this 32 document defines the Authorization Identity Request and Response 33 controls for use with the Bind operation. 34 35 1. Introduction 36 37 This document defines support for the Authorization Identity Request 38 Control and the Authorization Identity Response Control for 39 requesting and returning the authorization established in a bind 40 operation. The Authorization Identity Request Control may be 41 submitted by a client in a bind request if authenticating with 42 version 3 of the Lightweight Directory Access Protocol (LDAP) 43 protocol [LDAPv3]. In the LDAP server's bind response, it may then 44 include an Authorization Identity Response Control. The response 45 control contains the identity assumed by the client. This is useful 46 when there is a mapping step or other indirection during the bind, so 47 that the client can be told what LDAP identity was granted. Client 48 authentication with certificates is the primary situation where this 49 applies. Also, some Simple Authentication and Security Layer [SASL] 50 authentication mechanisms may not involve the client explicitly 51 providing a DN, or may result in an authorization identity which is 52 different from the authentication identity provided by the client 53 [AUTH]. 54 55 56 57 58 Weltman, et al. Informational [Page 1] 59 61 RFC 3829 Authorization Identity Bind Control July 2004 62 63 64 The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY" 65 used in this document are to be interpreted as described in 66 [RFCKeyWords]. 67 68 2. Publishing support for the Authorization Identity Request Control 69 and the Authorization Identity Response Control 70 71 Support for the Authorization Identity Request Control and the 72 Authorization Identity Response Control is indicated by the presence 73 of the Object Identifiers (OIDs) 2.16.840.1.113730.3.4.16 and 74 2.16.840.1.113730.3.4.15, respectively, in the supportedControl 75 attribute [LDAPATTRS] of a server's root DSA-specific Entry (DSE). 76 77 3. Authorization Identity Request Control 78 79 This control MAY be included in any bind request which specifies 80 protocol version 3, as part of the controls field of the LDAPMessage 81 as defined in [LDAPPROT]. In a multi-step bind operation, the client 82 MUST provide the control with each bind request. 83 84 The controlType is "2.16.840.1.113730.3.4.16" and the controlValue is 85 absent. 86 87 4. Authorization Identity Response Control 88 89 This control MAY be included in any final bind response where the 90 first bind request of the bind operation included an Authorization 91 Identity Request Control as part of the controls field of the 92 LDAPMessage as defined in [LDAPPROT]. 93 94 The controlType is "2.16.840.1.113730.3.4.15". If the bind request 95 succeeded and resulted in an identity (not anonymous), the 96 controlValue contains the authorization identity (authzId), as 97 defined in [AUTH] section 9, granted to the requestor. If the bind 98 request resulted in an anonymous association, the controlValue field 99 is a string of zero length. If the bind request resulted in more 100 than one authzId, the primary authzId is returned in the controlValue 101 field. 102 103 The control is only included in a bind response if the resultCode for 104 the bind operation is success. 105 106 If the server requires confidentiality protections to be in place 107 prior to use of this control (see Security Considerations), the 108 server reports failure to have adequate confidentiality protections 109 in place by returning the confidentialityRequired result code. 110 111 112 113 114 115 Weltman, et al. Informational [Page 2] 116 118 RFC 3829 Authorization Identity Bind Control July 2004 119 120 121 If the client has insufficient access rights to the requested 122 authorization information, the server reports this by returning the 123 insufficientAccessRights result code. 124 125 Identities presented by a client as part of the authentication 126 process may be mapped by the server to one or more authorization 127 identities. The bind response control can be used to retrieve the 128 primary authzId. 129 130 For example, during client authentication with certificates [AUTH], a 131 client may possess more than one certificate and may not be able to 132 determine which one was ultimately selected for authentication to the 133 server. The subject DN field in the selected certificate may not 134 correspond exactly to a DN in the directory, but rather have gone 135 through a mapping process controlled by the server. Upon completing 136 the certificate-based authentication, the client may issue a SASL 137 [SASL] bind request, specifying the EXTERNAL mechanism and including 138 an Authorization Identity Request Control. The bind response MAY 139 include an Authorization Identity Response Control indicating the DN 140 in the server's Directory Information Tree (DIT) which the 141 certificate was mapped to. 142 143 5. Alternative Approach with Extended Operation 144 145 The LDAP "Who am I?" [AUTHZID] extended operation provides a 146 mechanism to query the authorization identity associated with a bound 147 connection. Using an extended operation, as opposed to a bind 148 response control, allows a client to learn the authorization identity 149 after the bind has established integrity and data confidentiality 150 protections. The disadvantages of the extended operation approach 151 are coordination issues between "Who am I?" requests, bind requests, 152 and other requests, and that an extra operation is required to learn 153 the authorization identity. For multithreaded or high bandwidth 154 server application environments, the bind response approach may be 155 preferable. 156 157 6. Security Considerations 158 159 The Authorization Identity Request and Response Controls are subject 160 to standard LDAP security considerations. The controls may be passed 161 over a secure as well as over an insecure channel. They are not 162 protected by security layers negotiated by the bind operation. 163 164 The response control allows for an additional authorization identity 165 to be passed. In some deployments, these identities may contain 166 confidential information which require privacy protection. In such 167 deployments, a security layer should be established prior to issuing 168 a bind request with an Authorization Identity Request Control. 169 170 171 172 Weltman, et al. Informational [Page 3] 173 175 RFC 3829 Authorization Identity Bind Control July 2004 176 177 178 7. IANA Considerations 179 180 The OIDs 2.16.840.1.113730.3.4.16 and 2.16.840.1.113730.3.4.15 are 181 reserved for the Authorization Identity Request and Response 182 Controls, respectively. The Authorization Identity Request Control 183 has been registered as an LDAP Protocol Mechanism [IANALDAP]. 184 185 8. References 186 187 8.1. Normative References 188 189 [LDAPv3] Hodges, J. and R. Morgan, "Lightweight Directory Access 190 Protocol (v3): Technical Specification", RFC 3377, 191 September 2002. 192 193 [LDAPPROT] Wahl, M., Howes, T. and S. Kille, "Lightweight 194 Directory Access Protocol (v3)", RFC 2251, December 195 1997. 196 197 [RFCKeyWords] Bradner, S., "Key Words for use in RFCs to Indicate 198 Requirement Levels", BCP 14, RFC 2119, March 1997. 199 200 [AUTH] Wahl, M., Alvestrand, H., Hodges, J. and R. Morgan, 201 "Authentication Methods for LDAP", RFC 2829, May 2000. 202 203 [SASL] Myers, J., "Simple Authentication and Security Layer 204 (SASL)", RFC 2222, October 1997. 205 206 [LDAPATTRS] Wahl, M., Coulbeck, A., Howes, T. and S. Kille, 207 "Lightweight Directory Access Protocol (v3): Attribute 208 Syntax Definitions", RFC 2252, December 1997. 209 210 [IANALDAP] Hodges, J. and R. Morgan, "Lightweight Directory Access 211 Protocol (v3): Technical Specification", RFC 3377, 212 September 2002. 213 214 8.2. Informative References 215 216 [AUTHZID] Zeilenga, K., "LDAP 'Who am I?' Operation", Work in 217 Progress, April 2002. 218 219 220 221 222 223 224 225 226 227 228 229 Weltman, et al. Informational [Page 4] 230 232 RFC 3829 Authorization Identity Bind Control July 2004 233 234 235 9. Author's Addresses 236 237 Rob Weltman 238 America Online 239 360 W. Caribbean Drive 240 Sunnyvale, CA 94089 241 USA 242 243 Phone: +1 650 937-3194 244 EMail: robw (a] worldspot.com 245 246 247 Mark Smith 248 Pearl Crescent, LLC 249 447 Marlpool Drive 250 Saline, MI 48176 251 USA 252 253 Phone: +1 734 944-2856 254 EMail: mcs (a] pearlcrescent.com 255 256 257 Mark Wahl 258 PO Box 90626 259 Austin, TX 78709-0626 260 USA 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 Weltman, et al. Informational [Page 5] 287 289 RFC 3829 Authorization Identity Bind Control July 2004 290 291 292 10. Full Copyright Statement 293 294 Copyright (C) The Internet Society (2004). This document is subject 295 to the rights, licenses and restrictions contained in BCP 78, and 296 except as set forth therein, the authors retain all their rights. 297 298 This document and the information contained herein are provided on an 299 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 300 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET 301 ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, 302 INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE 303 INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 304 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 305 306 Intellectual Property 307 308 The IETF takes no position regarding the validity or scope of any 309 Intellectual Property Rights or other rights that might be claimed to 310 pertain to the implementation or use of the technology described in 311 this document or the extent to which any license under such rights 312 might or might not be available; nor does it represent that it has 313 made any independent effort to identify any such rights. Information 314 on the procedures with respect to rights in RFC documents can be 315 found in BCP 78 and BCP 79. 316 317 Copies of IPR disclosures made to the IETF Secretariat and any 318 assurances of licenses to be made available, or the result of an 319 attempt made to obtain a general license or permission for the use of 320 such proprietary rights by implementers or users of this 321 specification can be obtained from the IETF on-line IPR repository at 322 http://www.ietf.org/ipr. 323 324 The IETF invites any interested party to bring to its attention any 325 copyrights, patents or patent applications, or other proprietary 326 rights that may cover technology that may be required to implement 327 this standard. Please address the information to the IETF at ietf- 328 ipr (a] ietf.org. 329 330 Acknowledgement 331 332 Funding for the RFC Editor function is currently provided by the 333 Internet Society. 334 335 336 337 338 339 340 341 342 343 Weltman, et al. 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